1. Field of the Invention
The present invention pertains to the art of refrigerators and, more particularly, to a control for a refrigerator that establishes and maintains desired fresh food compartment and freezer compartment temperatures, as well as enabling various user selectable features.
2. Discussion of the Prior Art
In general, a refrigerator includes a first or freezer compartment for maintaining foodstuffs at or below freezing, and a second or fresh food compartment for maintaining foodstuffs in a temperature zone between ambient and freezing temperatures. A typical refrigerator includes a refrigeration system having a compressor, a condenser coil, a condenser fan, an evaporator, and an evaporator fan.
In operation, temperature sensors provided within the refrigerator are used to measure temperatures in the fresh food and freezer compartments. When a door associated with either compartment is opened, the resulting loss of cool air will cause the temperature of the compartment to rise. When the temperature of the compartment deviates from a predetermined or pre-selected temperature, the refrigeration system is activated to return the temperature to a point below a consumer or factory established set-point. In order to return the compartment temperature to this point, prior art systems are caused to operate at maximum capacity regardless of the degree of the deviation.
Prior art refrigerators typically employ a wide temperature zone or bounce region that establishes an acceptable temperature range in order to minimize operation of the refrigeration system. A small temperature zone or bounce region results in extended operation of the system, thereby reducing energy efficiency. On the other hand, a wide temperature zone causes temperature fluctuations that may negatively impact quality and/or taste of certain food items.
As part of the overall refrigeration system, a damper is typically provided between the freezer compartment and the fresh food compartment. Operation of the damper is controlled such that cool air is permitted to flow from the freezer compartment to the fresh food compartment. In some arrangements, a fan is mounted within a housing adjacent the evaporator to aid in establishing the airflow. Accordingly, if the temperature of the fresh food compartment rises above the set-point, the damper is opened to allow the passage of cooling air from the evaporator compartment into the fresh food compartment.
In addition, one or more fans have been incorporated into the fresh food compartment to circulate or evenly distribute the cooling air in order to minimize temperature stratification. Typically, the fan(s) is continuously operated when the fresh food door is closed. However, operating the fan when the damper is open may cause too much cooling air to be drawn into the fresh food compartment. In any event, in addition to controlling refrigeration components, dampers and fans, many refrigerators include controls that enable a consumer to selectively activate various features to tailor operation of the refrigerator to suit a particular need.
Regardless of the teachings in the prior art, there still exists a need for an enhanced refrigerator control system. More specifically, there exists a need for a refrigerator controller that combines operation of the damper and a fan in the fresh food compartment to maintain desired compartment temperatures. In addition, there exists a need for a controller that can determine a direction and magnitude of change of temperature in the fresh food and/or freezer compartments to provide greater sensitivity in order to minimize activation of the refrigeration system, as well as blend various user selectable features to obtain a synergistic combination that appeals to consumers.